Abstract: Disclosed is a humidity indicator which contains no heavy metal and has good visibility of a color change that occurs when the humidity is increased. The humidity indicator can be produced by applying an aqueous coating comprising a leuco dye, an acidic compound which is in a solid state at ambient temperature, a deliquescent substance and an aqueous resin emulsion onto a substrate such as a resin film, a nonwoven fabric or a paper, and heating and drying the resulting product.

Abstract: A humidity indicator including a coloration composition, which contains a deliquescent material, supported on a porous base material, wherein the adhesion of the coloration composition, which has been once printed and thus adhered to the base material, to a member or the like of a printer is inhibited in a production process to thereby reduce printing errors and the maintenance frequency of the printer. Furthermore, blocking which occurs in stacking multiple humidity indicators can be prevented. Beads not reacting with the constituting components of the coloration composition are dispersed into the coloration composition to form convex portions. Further, the coloration composition is coated with a top coat layer including beads dispersed in a resin.

Abstract: Disclosed is a humidity indicator which contains no heavy metal and has good visibility of a color change that occurs when the humidity is increased. The humidity indicator can be produced by applying an aqueous coating comprising a leuco dye, an acidic compound which is in a solid state at ambient temperature, a deliquescent substance and an aqueous resin emulsion onto a substrate such as a resin film, a nonwoven fabric or a paper, and heating and drying the resulting product.